Version 1626 was commited by steve on 2010-04-02 20:27:32 +0100 (Fri, 02 Apr 2010) In case multiple ways were joined to a polygon the polygon was tagged with the union set of tags of all joined ways. This algorithm is not compatible to the tag join algorithm described on the multipolygon relation definition (http://wiki.openstreetmap.org/wiki/Relation:multipolygon#Tagging). - WanMil